大约有 43,000 项符合查询结果（耗时：0.0516秒） [XML]
Repeat each row of data.frame the number of times specified in a column
...es
library(dplyr)
df %>%
slice(rep(seq_len(n()), freq)) %>%
select(-freq)
# var1 var2
#1 a d
#2 b e
#3 b e
#4 c f
#5 c f
#6 c f
seq_len(n()) part can be replaced with any of the following.
df %>% slice(rep(1:nrow(df), freq)) %>% select(-...
Why am I getting “Cannot Connect to Server - A network-related or instance-specific error”?
...ation
Click on Surface Area Configuration for Services and Connections
Select the instance that is having a problem > Database Engine > Remote Connections
Enable local and remote connections
Restart instance
You may need to create an exception on the firewall for the SQL Server ...
Remove non-ascii character in string
and i need to remove all non-ascii character from string,
5 Answers
5
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What is the advantage of using heredoc in PHP? [closed]
...e day I used to use them to construct SQL queries:
$sql = <<<SQL
select *
from $tablename
where id in [$order_ids_list]
and product_name = "widgets"
SQL;
To me this has a lower probability of introducing a syntax error than using quotes:
$sql = "
select *
from $tablename
where ...
CSS Input with width: 100% goes outside parent's bound
...il" class="login-field">
<label for="email" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">E-mail address</label>
<span><input name="email" id="email" type="text" /></span>
</div>
<div clas...
Xcode 4.4 error - Timed out waiting for app to launch
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I was trying to debug with a Enterprise Dist cert selected. Switched back to my development cert and the issue was resolved-- thanks!
– RyanG
Nov 19 '12 at 20:15
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What is meant by Resource Acquisition is Initialization (RAII)?
...s piece of code:
void fn(const std::string& str)
{
std::vector<char> vec;
for (auto c : str)
vec.push_back(c);
// do something
}
when you create a vector and you push elements to it, you don't care about allocating and deallocating such elements. The vector uses new ...
Archiving project in Xcode incorrectly creates multi-application bundle
...stall is set to No or which header files are causing the problem try this: Select the archive and click the Distribute button. Select the 'Save Built Products' option. Hit Next and Save. Browse the created directory in Finder. The 'libraries' subdirectory will identify the libraries that you need t...
MySQL table is marked as crashed and last (automatic?) repair failed
... This was a quick fix! Had a "bad" options table. Make sure that you select the correct database first !
– jyllstuart
Jan 10 '19 at 15:54
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How do I get a distinct, ordered list of names from a DataTable using LINQ?
...tainable, you can also split it up into multiple LINQ statements.
First, select your data into a new list, let's call it x1, do a projection if desired
Next, create a distinct list, from x1 into x2, using whatever distinction you require
Finally, create an ordered list, from x2 into x3, sorting by...